Characterization of PM2.5/PM2.5-10 and source tracking in the juncture belt between urban and rural areas of Beijing

Coarse （PM2.5-10） and fine （PM2.5） atmospheric particulate samples were collected in summer and winter during 2005-2007 in the juncture belt between urban and rural areas of Beijing. Elements, ions, organic/elemental carbon （OC/EC） and polynuclear aromatic hydrocarbons （PAHs） were determined to obtain some latest information about the particulate pollution in the juncture belt of Beijing. Particulate matter levels at this site were high as compared with the levels at other sampling sites in Beijing. Pollution elements, secondary ions and PAHs were enriched in fine particles rather than in coarse particles. An obvious seasonal variation of the chemical composition of PM was observed. Source apportionment results showed that secondary components were the largest mass contributor of PM2.5, accounting for 28%; whereas soil-related sources were the largest contributor of PM2.5-10, explaining about 49% of the total mass. The abnormal levels of soil heavy metals at the electronic waste disassembly site in the upwind villages suggested the potential impact of such activities to the environment.     

Apoptosis induced by titanium dioxide nanoparticles in cultured murine microglia N9 cells

Owing to the rapidly increasing output of nano-scale titanium dioxide （TiO2） particles, their potential risk for central nerve system （CNS） has elicited much concern recently. Microglia is the resident macrophage in CNS and essential for the homeostasis of the CNS microenvironment. They are supposed to response to nanoparticles depositing in the brain tissues. Therefore, we investigated the cytotoxic effects of TiO2 NPs on microglia N9 cells in vitro. Results of propidium iodide/fluorescein diacetate （PI/FDA） double staining and MTT test clearly showed that TiO2 NPs more efficiently affected the viability of microglia N9 cells. Further Hoechst 33258 staining and flow cytometric analysis proved that nano-scale but not normal scale TiO2 induced apoptosis in vitro, These data suggest that TiO2 NPs can elicit apoptosis of N9 cells in vitro and thus present a potential risk for CNS.     

利用故障方向信息的差动式微电网保护

针对传统的电流保护无法满足微电网保护的问题,提出了一种新型的微电网的系统保护方案。在该保护方案中,通过相邻保护单元之间互相交换带方向的故障信息,确定故障范围, 快速动作清除故障。最后通过分析一个包含三条支路和两个基于逆变器的微电源的微电网在三种故障情况下保护的动作,验证了该方法能够达到快速动作切除故障以及在并网模式和孤岛模式中采用相同的保护策略的目的。     

基于微粒群算法薄钢板磁场推算中的位置优化

基于积分方程法进行薄钢板两侧磁场推算时方程离散化后容易呈现病态,提出了一种依据磁场计算和剖分单元数进行测量点数的优化方法.该方法利用随机类微粒群(PSO)优化算法确定相应的测量位置分布,不但解决了测量位置优化问题,而且需要的测量点数较少,推算精度大大提高.通过钢板实验中2组不同测量位置的磁场推算实例,验证了优化位置的有效性.     

协同模式识别方法综述

介绍协同学理论的基本原理及常见的协同模式识别算法 ,有助于模式识别理论的进一步发展。介绍了相关的基本概念 ,重点对协同识别算法中的原型模式的选择及注意参数的设置等关键技术进行了综述。分析了各种常见方法的应用效果并进行了初步的评价 ,展望了协同模式识别算法的发展方向。协同模式识别方法是协同学原理应用于模式识别领域的一种新方法 ,该算法有着很好的发展前景     

基于Web的工作流管理系统及企业应用集成技术研究

基于 Web的工作流管理系统 (WFMS)是工作流研究领域重要的研究方向 .本文在分析工作流技术的基础上 ,提出应用 Web的通讯机制、以 CORBA解决分布式互操作 ,建立工作流管理系统 ,应用集成的思想 .并对 WFMS的安全问题进行了讨论.     

集对分析聚类预测法及其应用

提出一种新的预测方法－－集对分析聚类预测法，该方法融合了集对分析中的同异反模式识别的“择近原则”和聚类分析的基本思想进行分类预测，文中将该方法应用于于邮电业务总量预测的研究，研究，考虑了邮电业务总量和第一、二、三产业的国内生产总值之间的关系，利用邮电业务总量和三个产业的生产总值的历史数据，建立了邮电业务量水平聚类预测的模型，从而得到邮电业务总量预测结果，利用我国某地区的实际数据进行分析计算，并与其它预测方法比较，结果表明预测方法是有效的。     

Decoration of C60 nanorods with nickel and their magnetic properties

We studied the coating of C60 nanorods with nickel by electroless plating method and investigated their magnetic properties. The morphology and structure of the nickel layer coated on C60 nanorods were characterized by transmission electron microscopy （TEM）, energy-dispersive X-ray spectroscopy （EDX）, X-ray diffraction （XRD） and Raman spectroscopy. The coated nickel is in the form of nano-sized crystals and becomes a continuous layer as reaction time increases. The hysteresis loop shows a super paramagnetic characteristic similar to that of nanometer-sized nickel particle. These results suggest that the average size of nickel particles on C60 rods is below 10 nm. Our study has shown that electroless plating is an efficient and simple method for coating C60 nanorods with nickel.     

玉米幼胚的组织培养及其植株再生的研究

以成单１４,１５,１８三种基因型玉米为材料,对幼胚愈伤组织的诱导和继代培养,植株再生,再生苗的培养和移栽等方面进行了系统的研究,三种基因型玉米幼胚经诱导均可产生愈伤组织,但只有成单１５,１８两种基因型玉米幼胚产生的愈伤组织可继代培养下去。     

满汉计算机辅助翻译系统的满文字符编码

满文借助于蒙古文字母创制而成,是一种拼音文字,满文的拼接是以音节为单位进行的·“满汉计算机辅助翻译系统”首先建立了基于音素的满文编码,以及基于音节的满文输出与显示码,并在这两级编码之间建立起映射规则·在此基础上实现了一个满文编辑器,以及基于罗马转写的满文输入法·使用的编码方式,使满文的输入输出方便简单,并能同时适应满文印刷和满文信息深层次处理的需要·